The invention relates to a method for assigning tire pressure measurement devices in a motor vehicle to wheel positions and a device for measuring the tire pressure in any tire on a motor vehicle.
Such devices specifically have sensors inside the tire on each wheel, which specifically measure the air pressure in-side the tire. The air pressure is sent in the form of a measured value to an analysis device located in the motor vehicle. The analysis device compares the air pressure in the tire with a minimum admissible threshold value. If the measured value is below this threshold value, the analysis device can warn the driver that the tire pressure is too low.
So that the analysis device knows exactly which tire the low air pressure message relates to, the analysis device must be informed at least once during the journey which sensor and therefore which identification code is assigned to which wheel position. A method for assigning tire pressure measurement devices to wheel positions is, for example, known from patent specification EP 0 760 299 B1. There an additional sensor in the tire is used to identify the direction of revolution of the assigned wheel and transmit this to an analysis device. The analysis device is also informed of the direction of travel of the vehicle. This means that two pressure measurement devices can be assigned to each vehicle side, i.e. left or right.
In order to allow assignment of the tire pressure measurement devices to a front or rear wheel as well, with the known method the tire pressure values are compared with target pressure values on the front axle and rear axle. As, generally, the pressure level values are lower on the front axle than on the rear axle, assignment can then be made to a front or rear wheel. The combination of both methods allows assignment to a specific wheel position.
With the known tire pressure measurement device, the direction of revolution of the wheels is identified by means of revolution direction identification sensors. Such sensors are however very complex and expensive.